Rotating liquid diffuser devices as used in irrigation systems for delivery of water, commonly known as “sprinklers”, comprise a support frame which is designed to be connected to the hydraulic system and has a nozzle for directing the liquid jet to a diffusion plate.
The latter is conveniently formed with a plurality of radial grooves for peripheral jet delivery.
The plate may be fixed or move, under the thrust exerted by the jet, with a combined rotational and precessional motion about a central axis, for peripheral jet diffusion.
The area that can be reached by the deflected jet may vary according to the jet length and the plate shape.
Various diffuser solutions are known in the art, either with a rotary or fixed plate, or with a lance, which are designed to receive nozzles of various outlet diameters and allow adjustment of jet length for irrigation of areas of various sizes.
Some of these prior art solutions, as disclosed for instance in EP1738833 and U.S. Pat. No. 6,085,995, have a diffuser member with a plurality of fixed nozzles having different outlet sections, that can be selectively chosen by the rotation of a disk element.
Nevertheless, these prior art solutions require a complex fabrication process and also limit the types of usable nozzles to those available in the diffuser member.
U.S. Pat. No. 6,651,909 discloses a lance-type diffuser having a nozzle-holding plate designed for removable connection to the diffuser body and having a plurality of circular seats for respective nozzles to be snap fitted therein.
A first drawback of such solution is that the nozzle-holding plate is external to the diffuser, which increases assembly complexity and overall diffuser costs, and involves the risk of losing the plate.
Furthermore, this particular type of fit may lose its efficiency with time, upon repeated fitting of the nozzles into and out of their seats, which may thus be deformed or broken.
U.S. Pat. No. 5,762,269 discloses a rotating diffuser device with a frame that supports a liquid jet delivery nozzle at one end and a jet deflecting member at the other end.
The diffuser further has a plate composed of two rings, which is designed to be removably attached to the support frame at the jet delivery section.
One of the two rings will receive the nozzle in its operating position, and the other will be designed to support a replacement nozzle.
Whenever the operating-position nozzle needs to be replaced with the other nozzle, this will require dismantling of the upper portion of the frame, removal of the ring plate and 180° rotation thereof to move the replacement nozzle into the operating position.
It will be understood that this prior art solution suffers from the drawbacks of inconvenient use and long nozzle removal and replacement times.
Furthermore, the nozzle-holding plate is still external to the diffuser and susceptible of being lost.
Also, none of the prior art devices allows the user to simply and promptly identify the available nozzles.